The invention relates generally to an electric motor.
More particularly, the invention relates to an electric motor having a rotor and a stator both of which are provided with polyphase windings.
Various types of electric motors having polyphase windings in the rotor and stator are known. One such type of motor is the stepping motor. These motors have a wide range of applications in electromechanical systems where the position of the rotor, as well as a load being moved by the rotor, is regulated by a digital control system or computer.
The known stepping motors have a low nominal output torque which decreases rapidly with speed. Consequently, their use is limited to applications, such as line printers, requiring low torque. However, in certain applications, such as elevators, cranes and machine tools, precise positioning of heavy loads is required.